DESCRIPTION: The fundamental goal of this program is to develop a microfluidics-based artificial kidney that minimizes exposure of blood to artificial surfaces and provides continuous perfusion in a compact, wearable device. This device will provide treatment at low flow rates over long times, greatly reducing concentration and volume transient in body fluids. The key element is a primary separator that enables transport of water and solutes from the blood to a plasma-like solution (sheath fluid). The sheath fluid carries these compounds to a secondary separator where they are transferred to an external dialysate for disposal. The secondary separator is similar to a conventional membrane hemodialyzer or hemodiafilter, but is substantially smaller. It acts only on the sheath fluid to remove water and solutes and recycle purified sheath fluid to the primary separator. The nature of the system allows the majority of the components (the primary and secondary separators) to be worn in a small package approximately 60 cm3 in size. Thus far we have demonstrated the essential parameters of the primary and secondary separators and begun the design of other system components. We have worked closely with a commercial partner and present this proposal as a direct development path to the first product in an identified family of related medical devices. In the proposed Phase II program, we will finalize the design of all components of the system and perform preliminary testing such that by the end of the Phase II program we will be prepared to apply for an IDE for full clinical trials. PUBLIC HEALTH RELEVANCE: Standard treatment for End Stage Renal Disease (ESRD) is dialysis. Annual clinical costs for treatment of ESRD approach $10 billion, and market estimates indicate that almost 90% of patients are treated by hemodialysis. Hemodialysis, however, is far from a perfect solution, in that it requires thrice-weekly visits to a clinic, and leaves the patient feeling ill for a good portion of the time prior and immediately following these treatments. Our device will enable the maintenance of volume between treatments, and eventually replace clinical treatments, improving patient quality of life by virtue of providing slow treatment over many hours instead of a few relatively short sessions a week. By eliminating the need for frequent clinic visits, the patient is more able to lead a normal life. In summary, the device proposed here will serve the portion of that market that can be much more fully rehabilitated when freed from the regimen and deficiencies of in-clinic dialysis.